The FBI is investigating an arson fire at the Chinese consulate in San Francisco, an incident that has China's diplomats calling on the United States Thursday to "take all measures to provide adequate protection."

There is no indication the fire was an act of terrorism, FBI spokesman Peter Lee said.

According to a statement released by the consulate, footage from surveillance cameras shows the fire began Wednesday night after a person emerged from a parked mini-van, poured two buckets of gasoline on the front door of the consulate and ignited it.

"We strongly condemn this despicable attack," Wang Chuan, the consulate spokesman, told reporters during a news briefing outside the consulate. "We urge the U.S. side to take all necessary measures to provide adequate protection for Chinese consular personnel and properties."

Chuan characterized the fire as a "violent crime" that not only targeted the consulate but also its employees and residents living nearby.

There were no injuries reported in the fire, though a small number of employees were in the building when it began, Chuan told CNN affiliate KGO.

Surveillance video obtained exclusively by CNN affiliate KTVU appears to show a person standing in front of the consulate. Then seconds later on the grainy video, there is a ball of fire that erupts in front of the building, and the person can be seen walking to vehicle parked only a few feet away. The vehicle then drives off.

There have been no claims of responsibility for the attack, and the United States is not aware of a specific threat made against the consulate, State Department spokeswoman Marie Harf said.

"We take this incident very seriously," Harf said, adding that the United States is "deeply concerned" about the reported attack.